I completed an essay on the theological idea of Union with Christ as part of an intensive course at SMBC in July. I handed in the essay late (first time I have ever done so!) but still managed to gain 32/40 for it. I learnt a lot about the subject and hope it stirs some learning in those who read it.
In this paper we discuss the theme of Union with Christ and evaluate its contribution to our full understanding of salvation. What we find is that Union with Christ is a framework by which Paul connects all the doctrines together that are required for our full and eternal salvation. This is deduced by connecting the works of Jesus (along with the benefits that provides us) and how we are justified to being a direct consequence of our Union with Christ. We deduce that if it is the means by which we are connected with the work of our saviour, then our evaluation is that we cannot fully comprehend our salvation without understanding what it is to be united with Christ.
Union with Christ plays a crucial role in our understanding of Christian salvation. An accurate understanding of the concept will lead to a deeper and more significant comprehension when we consider what it means to be saved. This theme undergirds Paul’s theology of salvation and is presented as critical to the relationship to believers and central to the apostles thought. John Murray goes so far as to claim that ‘Union with Christ is really the central truth of the whole doctrine of salvation…’ In order to understand why it is so critical to our understanding of salvation, we must determine what it means and identify the role it plays. From there we can evaluate the full scope of Union with Christ and best see the part it plays in our understanding of Christian salvation.
Union with Christ as a theme is found primarily within the writings of Paul. Various scholars’ view it as the framework upon which Paul’s theology is built, which impresses on us the need to understand it properly. It saturates the apostle’s writing, appearing roughly 83 times in his writings. The primary way we see the concept expressed in Paul’s writings is through the formula ‘in Christ’.  It is used to describe various aspects of union; that we were baptized into Christ’s death (Rom 6:3-4), to state Christ in us is our righteousness, sanctification and redemption (1 Cor 1:30), that Christ became sin so that we might become the righteousness of God in Him (2 Cor 5:21), to signify that all are one in Christ Jesus (Gal 3:28) and that we are to grow into Him who is the head (Eph 4:15-16). Metaphor is also used to describe our union to Christ as akin to the body and its parts (1 Cor 12: 27-29), the marriage between man and wife (Eph 5:28-32) and a building with a cornerstone (Eph 2: 20-22). How Paul uses the formula also gives insight to how it is best interpreted; for example, Paul’s claim that ‘We were buried with him by baptism into death’ indicates the way we should interpret the meaning of the passage. This brief description highlights that Union with Christ is a wide ranging, or at least contextually broad, theological concept that touches on a number of different areas; justification, righteousness and adoption to name a few. But what did mean Paul by his use of the formula? Whilst we can determine what Union with Christ looks like, and indeed we see it in the scriptures, our understanding of it is limited because Paul doesn’t in any place explain it. This requires us to dig deeper in our exegesis to draw out what we believe Paul means by Union with Christ.
Let us turn first to the work of Christ. Campbell believes that ‘in the mind of Paul, union with Christ is inextricably linked to the work of Christ.’ The formula is often shown to be used objectively, subjectively and personally depending on the meaning he is intending to betray. We can see from Paul’s use of the formula that the phrase ‘in Christ’ is referencing the work of Jesus. In short, ‘whatever Christ did as our representative, God counted it as being we did too.’ But how is this conclusion arrived at?
Campbell distinguishes that within the formula, the use of the ‘σὺν ’ preposition in Greek where:
‘Participation with Christ in his work envisages a type of union that is not mediatorial so much as representative. As Christ performs his works, he represents believers while in some spiritual sense they partake in the events that he undergoes.’
Campbell’s statement is bold, as it means the believer is participating in the very acts of Christ that would grant us salvation! Yet this is clearly what Paul claims. Tannehill believes that this is an effort by Paul to further develop his soteriology in a bid to give deeper appreciation for Christ’s redemptive work as well as the consequences it brings. Acknowledging that we participate through Union with Christ in the work Christ accomplished answers, for all intents and purposes, the question of how we benefit from what took place in Christ.
This idea of our participation with the work of Jesus impacts most significantly when Paul suggests we have ‘died and risen with Christ’; how we understand this will define how we understand our salvation. If we believe that we have participated in the death and resurrection of Christ with Him as our representative, then Paul is declaring that we are no longer under the curse of sin and free also from death. Tannehill makes another grand statement that we should note:
‘If the believer dies and rises with Christ, as Paul claims, Christ’s death and resurrection are not merely events which produce benefits for the believer, but they are also events in which the believer himself partakes. The believer’s new life is based upon his personal participation in these saving events… it implies death to the old dominion of sin and new life to God.’
This is a startling revelation, as it is Paul’s ‘most encompassing explanation of how Jesus’ death and resurrection is salvific.’ It is here we should consider the Adam – Christ dichotomy that is the context for our participation. Parsons considers that ‘Paul seems rather to say that Adam’s descendants were involved in his sin and that Christ’s were involved, by imputation, in the ‘one act of righteousness’.’ This seems, at first, a fair statement to make. Yet this then begs the question ‘Why were Adam’s actions imputed to all?’ Campbell proposes, rather, that they represent two domains and humanity exists in one or the other. Dunn suggests that Adam and Christ acts as an ‘epochal figure’ and are the entry points to both domains, with ‘sin’ and the resulting death entering because of one, and ‘life-giving justification for everyone’ through the other. We are presented, therefore, with the purpose behind our Union with Christ and participation of his death and resurrection; ‘the transition out of the old domain of sin and death represented by Adam and facilitates entrance into the new domain of life and righteousness represented by Christ.’ This means, in summary, that we can identify with Christ’s representative death and resurrection ‘…and it facilitates a change of lordship as the believer dies to the dominion of sin and death and enters new life in the realm of Christ.’ Our participation via Union with Christ, then, is critical in our being drawn into the new sphere of life and righteousness and cannot, in fact, be achieved without it; consequently, it has a direct relationship with our salvation.
Recognising that we participate in Christs actions, we must now consider whether Union with Christ has an impact on our understanding of justification. Campbell argues that ‘justification occurs as an outworking of union with Christ.’ The question is, how? He articulates that Christ is the ‘agency’ in ‘producing justification’. Ridderbos agrees: ‘the foundation for the doctrine of justification… lies in the corporate unity of Christ and his own.’ Letham is helpful in describing how this is the achieved, citing the biblical language that identifies Christ as the substitute and representative for our atonement. The logic follows that as our substitute and representative:
‘…the wrongs done by the guilty parties have become Christ’s as well. In turn, the righteousness of the One who bears the punishment actually belongs to the other… because of the union sustained between Christ and ourselves, his actions are ours.’ 
What can be discerned from this is since we have shown that in our union we have participated with Christ, so too have we participated in the atonement achieved by Christ, who is our substitute and representative. Our righteousness, then, is imputed to us as an outworking of our Union with Christ. Carson and Campbell are deliberate in their attempts to ensure that there is no removal of righteousness from Christ to us; rather, it is, as far as the metaphor can be used, like uniting a cold coal with a fire so that it now shares the flames it did not previously have access to. Therefore, we can declare that our justification is ‘an outworking of union with Christ’, rather than a concept that sits in isolation from it. This leaves us with the conclusion that Union with Christ and justification are inescapably linked and cannot be achieved independently of each other. Further to this, since justification is the way in which we are ‘made right with God’, then we cannot properly understand our salvation without understanding Union with Christ.
Although a complete look at Union with Christ cannot be accomplished in this sitting, we can more appropriately ascertain what it is. We can define Union with Christ as ‘a phrase used to summarise several different relationships between believers and Christ, through which Christians receive every benefit of salvation.’ The definition supports the broad nature of Union with Christ without compromising the significance it holds to salvation.
With an understanding of what Union with Christ is and how it underlines doctrine concerning salvation, we are now in a position where we can more adequately evaluate the role it plays to our understanding of salvation. It is clear that two of the key facets relating to our salvation – the work of Christ and justification – are impacted by Union with Christ so it certainly plays a role; but does ignorance of the subject detract from a full comprehension of our salvation?
Union with Christ presents us with is a deeply intimate relationship. That a believer is united with their saviour identifies not just the importance it has in our comprehension of salvation but the outrageousness of Christianity – that we, sinful humans, might be united to the eternal God through His Son. But the fruit of this union is where we begin to fully appreciate the role it plays in salvation. Since our salvation is dependent on the finished work of Christ and the justification he has won for, and since our ability to benefit from those graces are derived from being united with Him, then Stedman is correct to state ‘in order to an interest in eternal life, and partaking of those blessings which are given forth by Christ… it is of absolute necessity that we be united unto Christ.’ Calvin concurs, surmising that ‘…we await salvation from him not because he appears to us afar off, but because he makes us, ingrafted into his body, participants not only in all his benefits but also in himself.’ Campbell believes ‘every element of Christ’s work’ is connected to Union with Christ. Gaffin considers Union with Christ, ‘sharing with him all he has accomplished and now is by virtue of his death and resurrection’, to be a core aspect of Paul’s soteriology. Without question, we cannot fully comprehend our salvation without properly understanding our Union with Christ.
As we see the importance Union with Christ plays to our very salvation, we finally see the contribution it makes to our understanding of salvation. Campbell again helps us here, stating that it is the ‘webbing that connects the ideas of Paul’s… theological framework’.  Although we cannot be saved without being justified by God, we are justified by God through our Union with Christ and participation in His works. Conversely, we cannot be united with God unless we are justified by Christ. What we can deduce from this is Union with Christ is the basket that holds the eggs of salvation and the whole doctrine is reliant upon this symbiotic relationship. Therefore, if we are to understand our salvation, we must comprehend our Union with Christ; for in this comprehension we find the pen that will join the dots and present us with a full picture of our very salvations.
Our study into Union with Christ has presented us with a powerful theme that runs throughout Paul’s writings. From a survey of the use of the ‘in Christ’ formula, we can determine it is a broad theological concept that has diverse meaning. When we exegetically investigate the text to determine its definition, it identifies that by being united to Him through His substitution and representation we have participated in His death and resurrection which justify us before God. Our understanding of Union with Christ is it is the relationship by which all things concerning salvation are imparted to us. From this we can evaluate its role in our understanding of salvation as the framework that draws together the doctrines that contribute salvation; without a full understanding of Union with Christ, we cannot properly understand how the benefits of salvation are imparted to us. In conclusion, Union with Christ contributes to a full understanding of salvation, and to neglect it would be to overlook the truly staggering truth that we are in Christ, and He is in us! Soli Deo Gloria.
 Grudem, Wayne. Systematic Theology: An Introduction to Biblical Doctrine. Leicester: IVP 1994. Pg 842
 Murray, John. Redemption Accomplished and Applied. Grand Rapids: Eerdmans, 1955, pg 161–73.
 Schweitzer, Albert. The Mysticism of Paul the Apostle. New York: Henry Holt, 1931, pg 22, Campbell, Constantine. Paul and Union with Christ: An Exegetical and Theological Study. Zondervan. 2012, pg444; Gaffin, Richard B. By Faith, Not By Sight: Paul and the Order of Salvation, Paternoster, 2006, pg35, Dunn, James D.G. The theology of Paul the Apostle, Grand Rapids: Eerdmans. 1998 pg397.
 Campbell, Constantine. Paul and Union with Christ, pg21, ‘Its prevalence on every page of his writings demonstrates his proclivity for the subject’, Parsons, Michael. ‘In Christ in Paul’. Vox Evangelica, 18 (1988): 25-44, pg25, Dunn notes the formula ‘in Christ’ occurs 83 times in Paul’s work, and that it is found almost exclusively in his writings Dunn, James D.G. The theology of Paul the Apostle. pg396
 Parsons and a number of other scholars consider the ‘in Christ’ terminology, along with phrases that are either contextually equivalent or linguistically similar as a formula Paul uses to convey Union with Christ. Parsons, Michael. ‘In Christ in Paul’. pg 25
 Romans 6:4, italics added; where possible, the English Standard Version translation has been maintained. Best gives an excellent summary of the manner Paul uses the ‘in Christ’ formula, which gives insight to how the formula links when used in different contexts and way. ‘1 ‘A is in Christ’: for example, Paul speaks of the saints ‘in Christ Jesus’ (Phil 1:1), of ‘those who are in Christ Jesus’ (Rom 8:1) and of himself as ‘a man in Christ’ (2 Cor 12:2). 2 ‘A does something to B in Christ’: the apostle urges the Thessalonians ‘in the Lord Jesus’ (1 Thess 4:1; cf Eph 4:17). 3 ‘A does something in the Lord’: in this way Paul exhorts the Philippians to ‘rejoice in the Lord’ (Phil 3:1; 4:4-10; cf 2 Cor 10:17). 4 ‘A is X in Christ’: Apelles is said to be tested and approved ‘in Christ’ (Rom 16:10) and Paul’s ultimate aim for his ministry is ‘to present everyone perfect in Christ’ (Col 1:28; cf 1 Cor 3:1). 5 ‘God gives us (does to us) something in Christ’: eg he forgave us in Christ (Eph 4:32; cf 1:6). 6 ‘…the gift of God … in Christ’ (eg Rom 3:24). 7 ‘A, B, C … are in Christ’ (eg Gal 1:22). It is interesting at this point that the Thessalonian church is said to be ‘in God our Father and the Lord Jesus Christ’ (1 Thess 1:1; 2 Thess 1:1). 8 The formula sometimes has cosmic significance, as it does in Colossians 1:16-17: ‘in him all things hold together’ (cf Eph 1:9-10; 3:10-11). 9 The use of the phrase in Colossians 2:9 deserves singular mention: ‘For in Christ all the fullness of the deity lives’’. Best, Ernest. One Body in Christ: A Study in the Relationship of the Church to Christ in the Epistles of the Apostle Paul. London: SPCK. 1955, pg 8-19
 Campbell, Constantine. Paul and Union with Christ, pg 21
 Campbell, Constantine. Paul and Union with Christ Pg 327
 Dunn, James D.G. The theology of Paul the Apostle, 397-398. With reference to the work of Christ, this is a subjective use, as it is about believers being ‘in Christ’, rather than the redemptive acts Christ has accomplished.
 Paul’s use of the term implies that we participate in redemption (Rom 3:24), the gift of eternal life (Rom 6:23, 2 Tim 1:1) sanctification (1 Cor 1:2), God’s gift of grace (2 Tim, 1:9); the list goes on. See Campbell, pg330-331 for a more complete survey.
 Grudem, Wayne. Systematic Theology, pg841.
 Campbell, Constantine. Paul and Union with Christ, pg332 The preposition, in Greek, is σύν.
 An example, which we will deal with in more detail shortly, is Romans 6:6-8.
 ‘When Paul shifts to participatory language in Romans 5:12-21 and Romans 6:1-7:6, speaking of dying and rising with Christ and describing Adam and Christ as supra-individual persons, he has not moved on from soteriology to a new topic but is deepening his soteriology, providing further insight into how redemption in Christ Jesus has taken place and explaining its implications.’ Tannehill, Robert C. “Participation in Christ: A Central Theme in Pauline Soteriology.” In The Shape of the Gospel: New Testamnt Essays, pp.223-37, Eugene: Cascade. 2007, pg235
 Ridderbos, Herman. Paul: An Outline of his Theology. pg58
 Campbell, Constantine. Paul and Union with Christ, pg337
 Tannehill, Robert C. Dying and Rising with Christ: A Study in Pauline Theology. Eugene: Wipf & Stock. 2006, pg1, 9. Wisnefske says much the same. ‘Christianity announces a cataclysmic breach in the ages: our former lives are moribund and passing away; but new life, the very life of God, is united with us and recreating us.’ Wisnefske, Ned ‘Living and Dying with Christ: Do we mean what we say?’ Word and World. 10, (1990), pg254-59, pg254
 Callan, Terrance. Dying and Rising with Christ: The theology of Paul the Aposlte. New York: Paulist. 2006, 93
 The context is Romans 5:12-21.
 Parsons, Michael. ‘In Christ in Paul’. pg30
 Campbell, Constantine. Paul and Union with Christ, pg342.
 Dunn, James D.G. Romans 1-8, World Biblical Commentary. Dallas: Word, 1988, pg289, Rom 5:12,18.
 Campbell, Constantine. Paul and Union with Christ, pg347 Hooker elucidates: ‘…it is arguable that for Paul the idea of human solidarity is vitally important factor in the substructure of his thought, more fundamental than all the images he uses; and that for him, man’s redemption is seen primarily in terms of moving from the sphere of Adam to the sphere of Christ’. Hooker, Morna D. From Adam to Christ: Essays on Paul. Eugene: Wipf & Stock, 2008, pg41.
 Campbell, Constantine. Paul and Union with Christ, pg352
 For the purposes of this essay I am using Grudem’s definition of justification, which is ‘…an instantaneous legal act of God in which he (1) thinks of our sins as forgiven and Christ’s righteousness as belonging to us, and (2) declares is to be righteous in his sight.’ Grudem, Wayne. Systematic Theology, pg723
 Campbell, Constantine. Paul and Union with Christ, pg396
 Campbell, Constantine. Paul and Union with Christ pg389; He draws this out by examining the formula ‘in Christ’ with reference to the instrumentality of Christ in becoming our righteousness in Gal 2:16,17, 2 Cor 5:21, whilst determining that through our union with Christ, we gain and share in Christs righteousness. (Phil 3:9)
 Ridderbos, Herman. Paul: An Outline of his Theology. Trans. John Richard de Witt. Grand Rapids: Eerdmans. 1982, pg169
 Regarding Christ as our substitute: Luke 22:19, 1 Cor 11:24, John 6:51, 1 Cor 15:3; regarding Christ as our representative: Rom 4:25, Rom 5:12-21, Heb 4:14; Letham, Robert (2011-10-21). Union with Christ: In Scripture, History, and Theology . P&R Publishing. Kindle Edition, Loc 1198
 As a consequence of our justification, we are declared righteous. Grudem, Wayne. Systematic Theology pg725
 Campbell, Constantine. Paul and Union with Christ, pg400. So too Vickers: ‘It is difficult to overemphasise that the imputation of Christ’s righteousness takes place in union with Christ. Only as a person is identified with Christ is Christ’s righteousness imputed to that person.’ Vickers, Brian J. Jesus’ Blood and Righteousness: Paul’s Theology of Imputation. Wheaton: Crossway. 2006, pg237
 ‘Imputation ought to be undertood as the unmerited reception of a righteousness that belongs wholly to another, and this reception of ‘alien’ righteousness is facilitated through the ‘un-alienation’ of two parties; once believers are joined to Christ, his righteousness is shared with them.’ Campbell, Constantine. Paul and Union with Christ, pg401. Carson also: ‘On the one hand, justification is, in Paul, irrefragably tied to our incorporation into Christ, to our union with Christ… If we speak of justification or of imputation… apart from a grasp of this incorporation into Christ, we will constantly be in danger of contemplating some sort of transfer apart from being included in Christ, apart from union with Christ.’ [italics are original] Carson, D. A. ‘The Vindication of Imputation’. Pages 46-78 in Justification: What’s at stake in the current debates. Ed Mark Husbands and Daniel J. Treier. Downers Grov: Eerdmans. 2008, Pg72,
 Campbell, Constantine. Paul and Union with Christ, pg405.
 Grudem, Wayne. Systematic Theology, pg841. I believe Campbell and Gaffin offer more detailed definitions of what Union with Christ is, but given the complexity of the subject and the inability to address the entire theme, to use such definitions would be to fully define the subject without fully addressing it. To see their thoughts, see Campbell, Constantine. Paul and Union with Christ, pg420 and Gaffin, Richard B. The Centrality of the Resurrection: A study into Paul’s Soteriology. Grand Rapids: Baker. 1978, pg130-132
 Ephesians 5:31-32 Paul’s decision to liken Union with Christ to marriage highlights it is the most profound type of relationship we can share with our saviour.
 Stedman, Rowland. The Mystical Union of Believers with Christ, or A Treatise Wherein That Great Mystery and Priviledge of the Saints Union with the Son of God Is Opened London: W. R. for Thomas Parkhurst, 1668, 335:13.
 Calvin, John. Institutes of the Christian Religion. Ed. By John T. McNeill, Trans. Ford Lewis Battles. Philadelphia: Westminster John Knox. 2006, 126.96.36.199
 Campbell, Constantine. Paul and Union with Christ, pg331. He accentuates his point by stating ‘Salvation, redemption, reconciliation, creation, election, predestination, adoption, sanctification, headship, provision, his death, resurrection, ascension, glorification, self-giving, the gifts of grace, peace, eternal life, the Spirit, spiritual riches and blessings, freedom, and the fulfilment of Gods promises are all relates to union with Christ.’ Pg331-332
 Gaffin, Richard B. By Faith, Not By Sight: Paul and the Order of Salvation, Paternoster, 2006, pg40
 Campbell, Constantine. Paul and Union with Christ pg442
 Romans 6:1-14